1. Field of the Invention
The invention relates to a hybrid vehicle which includes an engine and a motor as a power source.
2. Description of Related Art
In the related art, a hybrid vehicle which includes an engine and a motor as a power source is known. In such a hybrid vehicle, a traveling mode is selectable among a mode in which the vehicle travels only with engine power, a mode in which the vehicle travels with power of both of the engine and the motor, and a mode in which the vehicle travels only with the motor, according to a vehicle state or a driver's operation.
In the hybrid vehicle described above, for example, lubricating oil, such as an automatic transmission fluid (ATF), is supplied to the motor as a refrigerant to cool the motor which generates heat by rotational drive. A clutch may be disposed between the engine and the motor, and lubricating oil described above may be used as a hydraulic fluid for engaging or disengaging the clutch.
For example, Japanese Patent Application Publication No. 2013-207929 (JP 2013-207929 A) discloses a hybrid vehicle including pressure control means for regulating a line pressure of oil fed with pressure from a mechanical pump driven by engine output or an electric pump driven by a dedicated drive motor. In this hybrid vehicle, oil with the line pressure regulated by the pressure control means is supplied to a motor for traveling as a refrigerant, and is supplied as hydraulic oil for engaging or disengaging a clutch disposed between the engine and the motor.